Method of treating aluminous materials.



UNITED s rAirnsrntrnnr onnro.

ALDUS on-reems, F woncEs'rER, MASSACHUSETTS.

METHOD OF TREATING ALUMINOUS EATERIALS.

To all whom may it concern:

Be it knownflthat I, ALDUS C. HIGGINS, a citizen of the United States,residing at Worcester, in the county of Worcester and 'State ofMassachusetts, have invented cer-' tain'new and useful Improvements inMethods of Treating Aluminous Materials, of

. which the following is a specification;

like to a high conditions. I j

The material produced by the-fusion of This invention relates to thetreatment of artificially prepared aluminous materials, and particularly'the' roduct commercially used as an abrasive, t e object of theinvention being to provide a method of treating such materials to renderthem better adapted for the manufacture of abrasive imp ments orarticles and for other purposes.

According to the invention such materials are subjected preferably afterthey have been crushed or otherwise subdivided into fragments of a sizeadapted for use or for the preparation of abrasive implements and thetemperature under oxidizing alumina, raw or calcined bauxite or otheraluminous material-in the electric furnace and commercially used as anabrasive usually contains as non-essential ingredients or impuritiessmall proportions of such elements as iron, titanium and slllcon, orcompounds or alloys'of'these. As the electric iurnace smelting proceedsunder reducing conditions,' due to the use of carbon elec-- trodes or insome cases to the. admixture'of small proportions of carbon with thecharge, these several metals may occur '111 thelr re- .duced' ormetallic form, or as alloys, c'arbids .or oxids, more or lessdisseminated through These non-essential bodies occur in the implementsor articles prepared out the product.

from the abrasive material and areoften somewhat irregularlydisseminated therein;-

they are subject to oxidation or other change or transformation in theafter-treatment of these implements or articles, and give rise toobjectionable local modifications of the material or structure.

I have" found that the above objections maybe avoided byproceeding'substantlally as follows: The roduct prepared 1n the usualmanner by using an aluminous-material in the electric furnace is.crushed, preferably although not necessarily to such size or sizes asmay be suited for the subsequent manufacture. of abrasive implements vor Specification of Letters Patent. i Application filed ma 31, 1907. seial'm. 376,565.

subjecting. such materials,

Patented Aug. 10, 1909.

articles, and is then subjected to a roasti'ng operation under.oxidizing conditions, the temperature, duration and conditions of theroasting being-so controlled as to secure as completeoxidation of theimpurities or nonessentlal components as Is practlcable, or

such degree of oxidation thereof that no further substantialtransformation of these 1m urities will occur in'the course of the susequent firing of the implements or articles. The roasted material maythen be subjected to further treatment, as grinding or crushing, Washingwith Water or with acid .or alkaline solutions grading, etc. and may Jthen be molded and ed in the usual manner, using any of the customaryvitrified or potte bonds, as for instance a mixture of clay an felds ar;or the suitablyv graded material may be irectly utilized, or may beapplied to the production of articles not requiring firin as forinstance abrasive a ers and the ike; for. this latter use it is mind topresent particular advanta es.

The product treated as a ove is uniform in character, and implements orarticles prepared therefrom by bonding either with or without firingvare found to possess increased strength and durability.

Iclaim:

1. The method of treating artificially prepared alu-minous materialswhich consists in subjecting such materials, suitably subdivided, -to'heat under oxidizing conditions, and thereby oxidizing impuritiestherein.

2. 'l'he method of. treating artificially prepared aluminous materialswhich consists in ALDUS o. HIGGINS.

Witnesses A F. H. LINCOLN, -C.-

SMITH.

